Method and apparatus for forming undulating conduit

ABSTRACT

Method and apparatus for forming conduit or pipe of various sizes into undulating, helical pipe by feeding a length of conduit at a controlled rate through a bending mechanism while also continuously rotating the pipe at a controlled rate so that bending occurs in multiple axis directions and the diameter of the helical path of the conduit centerline of the coil is less than the conduit diameter, the pitch is greater than the pipe diameter, and a straight open channel is retained through the pipe coil.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a divisional application of U.S. applicationSer. No. 11/956,707 filed Dec. 14, 2007, which is presently pending.U.S. application Ser. No. 11/956,707 and the present application claimpriority under 35 U.S.C. §119(e) to U.S. provisional patent applicationNo. 60/874,848, filed Dec. 14, 2006, which is incorporated by referencein its entirety herein.

FIELD OF THE INVENTION

This invention pertains to a method and apparatus for forming bentconduit or pipe of various sizes that can be used for a variety ofapplications, including but not limited to hydrodynamic mixing with nomoving parts, generally known in the industry as a static mixer. Thisinvention provides a method and apparatus which can be utilized to formthe undulating conduit disclosed and claimed in my below mentionedapplications and U.S. Pat. No. 6,896,007, which is highly effective forextraction of oil from oil sands deposits present in many countriesthroughout the world.

BACKGROUND OF THE INVENTION

Various methods and apparatus are employed to bend or form lengths ofpipe. In U.S. Pat. No. 4,317,353, an automated apparatus is shown forforming helical corrugations in tubing by a twisting operation. However,such apparatus and methodology creates ridges and valleys in theinterior of the pipe, which when formed as shown in the reference, canproduce undesirable flow properties for fluid passing through the pipe.Furthermore, such apparatus and methodology would not likely bepractical for large-diameter conduits or for pipes made of certainmaterials. A hydraulic pipe bender is disclosed in Sheen U.S. Pat. No.5,431,035 issued Jul. 11, 1995. As with all prior bending operations,the pipe is bent only in one axis direction and it is not undulating inthe interior.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the present invention provides the methodology andequipment to form undulating conduit or pipe, which is bent in multipleaxes directions in the nature of a helix, and where the conduit or pipediameter is larger than the diameter of the helical path of the conduitcenterline.

The invention comprises forming conduit of various diameters including,but not limited to, large size conduit or pipe, into an undulatinghelical pipe. The conduit used may be any suitable shape in its internaldiameter (such as round), but preferably relatively continuous andsmooth. The external cross section of the conduit may be any suitableshape. The coil is formed by feeding the conduit or pipe at a controlledrate through a bending mechanism while also rotating it at a controlledrate such that bending occurs in multiple axis directions through 360degrees. The diameter of the resulting helical path of the conduitcenterline is less than the pipe diameter, while the pitch is greaterthan the pipe diameter so that a straight open circular channel isretained through the pipe coil. The combination of the helical shape ofthe internal walls of the conduit and the straight open round channelthrough the pipe coil imparts hydrodynamic mixing particularly toslurries flowed through the pipe.

A method is disclosed of forming an undulating pipe comprising,providing a substantially straight pipe having a longitudinal axisthrough the center of the pipe, providing a bending apparatus includinga system for feeding the pipe through the bending apparatus, moving thepipe in an axial direction through the bending apparatus, the bendingapparatus asserting a force on the pipe to arcuately bend the pipe, andsimultaneously rotating the pipe about the longitudinal axis as the pipeis moving in the axial direction such that the pipe undulates in agenerally helical path.

The bending apparatus may include a plurality of rollers. The bendingapparatus may comprise a feed roller and a bending roller. The interiorof the pipe may include a continuous smooth interior wall throughout alength of the pipe. The pipe may have an interior wall that is circularin cross-section at every position along a length of the pipe. The pipemay be moved and rotated at rates such that the pitch is substantiallygreater than one pipe diameter. The pipe may be moved and rotated atrates such that the pitch is a multiple of the pipe diameter. The pipemay be moved and rotated at rates such that the radius of the helicalpath is smaller than the radius of the interior of the pipe.

An undulating pipe formed by the method is also disclosed. Theundulating pipe may be a hydro-dynamic static mixing apparatus forflowing fluidized slurries, the pipe having a preselected andpredetermined configuration and length for mixing and/or transportingvarious substances including highly abrasive solids contained inslurries, said pipe being interconnected into a transportation andprocessing separation system for such slurries, said pipe having aninternal radius rc and the undulations are formed by a coil having aradius rh such that the diameter of the conduit is greater than the coildiameter, means for pumping said fluidized slurry through an undulatinginterior of the pipe at some stage of transportation through theseparation system, and said undulating interior configuration causingdynamic mixing of flowing slurries as said slurries are pumped throughthe pipe.

The undulating pipe may be a hydrodynamic static mixing apparatus havinga preselected and predetermined configuration and length for mixingand/or transporting various substances, including fluids and solidscontained in slurries, said pipe having an interior forming a helicalcoil having a pitch and with the diameter of the interior being greaterthan a coil helix diameter, said pipe including a generally roundinternal cross-section having a radius rc and a generally helicalundulation having a path radius rh, said pipe, including an open innerchannel along the longitudinal axis of the conduit, the inner channelhaving a radius ri that is substantially equal to rc−rh, the pitch ofthe helical coil being greater than one pipe diameter and said pipe isadapted to be incorporated into systems that perform one or more of thefunctions of fluid or slurry transport, processing and separation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagrammatic view of the working principle of the presentinvention for straight-feed without rotation;

FIG. 2 is a diagrammatic view showing the operation of the bendermechanism with controlled feeding and controlled rotation to formundulating pipe;

FIGS. 3 a and 3 b are two-dimensional illustrative side sectional viewsof a formed conduit;

FIG. 3 c is an end view showing the undulating configuration withdesired open channel interior produced by the bending operation;

FIG. 4 a is an end view of a length of helically undulating conduithaving a circular cross-section and an open center channel;

FIG. 4 b is a shallow perspective side view of the helically undulatingconduit of FIG. 4 a;

FIG. 4 c is a steep perspective side view of the helically undulatingconduit of FIG. 4 a;

FIG. 5 is an illustrative representation of the end views of severalalternative cross-sectional shapes for undulating conduits;

FIG. 6 a is an illustrative side view of an alternative form ofundulating conduit mixer in which the pitch of the helical undulation isnon-zero and the radius of the helical undulation is zero, for the casewhere the undulating conduit has an oval cross-section and the directionof rotating undulation is abruptly reversed to provide a short region ofintense mixing in the conduit;

FIG. 6 b is a magnified end view of the conduit in FIG. 6 a, showing theopen central channel provided by a spiral-twisted undulating conduithaving an oval cross-section;

FIG. 6 c is an illustrative trimetric view of a short section of theconduit of FIG. 6 b inserted as a flow revitalizer between two sectionsof standard cylindrical pipe;

FIG. 7 is a flow diagram of an oil sands bitumen extraction methodutilizing undulating conduits of the present invention;

FIG. 8 is a simplified diagram showing various pipe cross-sectionsshowing a settling of solids to the bottom of the pipe such as wouldoccur when the flow through the pipe has stopped; and

FIG. 9 is a simplified end view of a length of helically undulatingconduit having a circular cross-section and an open center channel.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a method and apparatus for forming an undulatingpipe having a helical interior path. A pipe of this kind may be used forthe transmission of fluids or slurries. The helical undulating shape mayhelp to transmit slurries in such a manner that solids disposed withinthe fluid may travel in a suspended state to limit the amount of solidmaterial that may collect near the bottom of the pipe.

For example, in the application of oil field drilling, it is common thatthe oil slurry removed from the earth would contain a mixture of liquidand solid particles, such as oil sands. This mixture is commonlytransported from the drilling site to a remote location for separationof the slurry. In straight pipes, the solid material in the slurry tendsto collect near the bottom of the pipe, thus obstructing transport. Inpipes having undulation in a single plane, the solid material tends tocollect in the valleys of the undulating pipe and the abrasiveness ofthe slurry wears down the pipe. The invention provides a method offorming a pipe having an interior that undulates in a helical path suchthat the solid material is substantially transported in a suspendedstate in the fluid.

An example of a machine capable of bending conduit is shown for examplein U.S. Pat. No. 5,431,035, incorporated herein by reference. Thebending machine may comprise frame elements, rollers, gears, a clutch,mechanisms for lifting, guiding, feeding and bending, and operatingsystems including, for example, electronic controls and hydraulics.Referring to FIG. 1, a system of rollers 102 is shown with a pipe 100progressing thereby in a single direction for accomplishing single-axisbending of the pipe 100. As shown, roller 104 imparts the bending forceon the pipe 100, while rollers 102 serve as feed rollers for directingthe pipe toward the roller 104. The roller 104 is offset with therollers 102 to bend the pipe. The resulting pipe formed by such aprocess is curved into a coil having a relatively large radius ofcurvature. It will be appreciated that any suitable number of rollersmay be utilized to form a pipe having an undulating helical interiorpathway.

Turning to FIG. 2, a mechanism is provided to impart a rotation to thepipe 100 as it progresses through the system of rollers 102. Therotation mechanism may continuously and controllably rotate the pipe 100along with a controlled feed rate. The revolving rate determines thediameter of the helix of the coil and the feed rate controls the pitchor length of a single undulation imparted to the pipe. Examples ofundulating pipe having various pitches are shown, for example, in FIGS.3 a and 3 c. The desired relationships for a pipe suitable intransportation, conditioning and separating oil sands, or for thetransportation of oilsands tailings, for example, include having thediameter of the helical path of the conduit centerline which is lessthan the pipe diameter, a pitch that is a substantially greater than thepipe diameter (and in some embodiments, approximately a multiple of thediameter) and an open channel through the pipe. The properties of theundulating helical pipe as specified herein may be useful in thetransportation of slurries containing abrasive solids in order to createa mixing effect to suspend the solid material in the slurry and also toreduce the amount of wear experienced in the interior of the pipe.

In some embodiments, the interior wall of the pipe has a continuoussmooth surface, although it will be appreciated that the interiorsurface may have any suitable surface property. Furthermore, in someembodiments, the interior wall may be round in cross-section throughoutthe length of the pipe, although it will be appreciated that the pipeinterior may have any suitable shape. A representative set of examplecross-sectional shapes is shown in FIGS. 5 a-5 d. It will also beappreciated that the exterior of the pipe may be any suitable shape. Forexample, the exterior of the pipe may be generally circular as shown inFIG. 2. In other embodiments, the exterior of the pipe may benon-circular. In some non-circular embodiments, the feeding and/orbending mechanisms may need adjustment to accommodate the non-circularshape, and/or a framing mechanism may be utilized around the pipe.

The diameter and pitch of the undulating pipe may be tailored, withinthe defined parameters, to best suit the particular application for thepipe whether it is for maximizing the effectiveness of static mixing,conditioning of oilsands slurries for maximum oil recovery, or formaximum reduction of pumping horsepower and wear for tailings transport.Moreover, by varying the feed rate of smaller diameter conduit throughthe machine, along with the rate and direction in which it is rotated, awide variety of pitch and helix diameters, with either left handed orright handed rotational direction, can be interspersed in the samelength of conduit in order to achieve multiple hydraulic objectives. Itwill be appreciated that the pipe used in oil filed applications istypically large diameter pipe, such as described further below, however,it will be appreciated that an undulating helical pipe of any suitablediameter may be formed as described herein.

FIG. 8 shows a variety of cross-sectional positions along the pipelength. As shown, when the flow of slurry is stopped, the solid material106 in the slurry may settle toward the bottom of the pipe and theliquid portion 108 of the slurry will generally occupy the remainder ofthe pipe interior. Specifically, this figure estimates the level ofsettled sand in a pipe (in horizontal position), when slurry flow ofabout 65 wt. % solids is suddenly interrupted. When flow restarts,resuspension of settled solids is aided by transverse secondary flows inthe liquid moving through the open pipe cross-section above the settledsolids.

FIG. 9 is a simplified end view of a undulating helical pipe showing theopen pathway through the pipe, the radius of which is represented byr_(i). The radius of the conduit is represented as r_(c). The radius ofthe helical path of the conduit centerline is represented by r_(h).

The Undulating Conduit Hydrodynamic Mixer—The undulating conduithydrodynamic mixer is the physical plant that provides controlledcontinuous positive dynamic interaction within the transported slurry.The undulating conduit creates the optimum environment for mixing of theoil sands slurry. The action may be described as directional flowchanges, accelerating and decelerating, twirling, spiraling, gyrating,folding the slurry over on itself and stretching the mixture as it istransported.

The above pattern of dynamic flow provides several advantages usuallynot available in present mixing systems.

Referring to FIGS. 3 a and 3 b, the undulating conduit hydrodynamicmixer is a static mixing apparatus of a preselected and predeterminedlength of elongated tubular conduit. It allows for mixing andtransporting various substances including highly abrasivesolids-containing slurries. As further discussed herein, the conduitmember can be interconnected into a transportation and processingseparation system.

In accordance with the present invention, the undulations may take avariety of serpentine paths or shapes with various pitches (FIG. 3 a-3c), repetitive or varying waves and differing cross sections, FIGS. 4, 4a, 5, 6. The undulations can be, of a helical type formation (i.e., coilspring configuration) such as could be advantageously used for roundpipe cross-sections, or a spiraled screw type shape for pipes of oval,polygonal, or other geometric cross-sections or combinations thereof, orthe undulations can be sinusoidal when the conduit is not free toundulate in three dimensions.

It is not necessary that the conduit walls be of uniform thickness. Forexample, the exterior surface of the conduit could have a cylindricalpipe shape, while the interior surface of the conduit could have anundulating shape, thereby forming an undulating passage inside anexternally cylindrical pipe of varying wall thickness. Such a design isparticularly appropriate for small diameter undulating conduits or forrelatively short ‘revitalize’ sections of undulating conduit. It will beappreciated that the use of other than round conduit, or other than amathematically precise helix for the path of undulation, is alsopermissible as well without deviating from the intent of this invention.

Helical type undulations are defined by geometry, having parameters suchas conduit radius, radius and pitch of the helical path of the conduitcenterline, the offset between the centerline of the conduitcross-section and the centerline of the helical path, and the inner andouter radii of the resulting conduit undulations.

Spiraled screw-shaped undulations are a special case of helicalundulation in which the radius of the helical path undulation is zerobut the pitch of undulation is non-zero. Spiraled screw undulations canbe defined by parameters such as the spiral screw pitch, the offsetbetween the conduit cross-section centerline and the centerline of thespiral path, and the cross-sectional shape of the conduit, for instance,oval, elliptical, semicircular, polygonal, or a combination thereof, orother non-circular shape.

Undulations can be formed by indenting the outside of a conduit in aspiraled screw type manner. The indentations can be grouped and placedat predetermined intervals. In an example for conduits containingslurried solids, the indentations may be limited to the upper portion ofthe conduit only and do not extend around the full circumference.Upper-surface indentations leave a straight conduit bottom that offersless resistance to sliding solids, is less prone to wear, and has nopockets to capture settled solids and impede resuspension during startupafter a shutdown. During restart, the upper-surface undulations createcurrents angled down toward the conduit bottom, which disturb thesettled solids and revitalize the flow.

Resuspension of Settled Solids. —In yet another embodiment of theUndulating Conduit Hydrodynamic Mixer, it is particularly advantageousfor the conduit to follow a helical path whose radius r_(h) is less thanthe conduit hydraulic radius r_(c). This configuration provides an openinner channel of radius r_(i)=r_(c)−r_(h) along the longitudinal axis ofthe undulating conduit, through which it is possible for fluid to flowin a straight line without undulation. With this configuration, even ifthe lower undulations of the conduit are almost completely plugged withsettled solids after an unplanned shutdown, this center channel allowsfluid to be pumped through the unplugged upper undulations of theconduit. The flow follows the conduit's upper undulations and developsprimary and secondary motions that aid resuspension of settled solids inthe conduit's lower undulations, thereby returning the entire conduit tothe fluidized flow condition.

Premature Separation/Stratification. —The transportation of slurries ofvarious compositions particularly in large diameter straight pipes(10″+) tends to give rise to premature separation and/or stratificationof elements.

By choosing appropriate geometry parameters, the undulating conduithydrodynamic mixer lends itself to precise control and thereforemanagement of the flow, while the alternating primary and secondary flowpatterns create a mixing effect which prevents premature separation andstratification of fluid components transported within the pipeline.

Flow Velocity. The swirling action in the undulating conduithydrodynamic mixer keeps solids in constant suspension, which means thatdeposition of solids along the base of the pipe is considerably lessthan in a straight pipe; ergo, lower velocities of slurry travel arefeasible without causing deposition. The lower velocity significantlyreduces the abrasive effect of the solids.

Slurry Conditioning. The entry of screened slurry into the undulatingconduit hydrodynamic mixer, brings with it lumps of oil sand reduced insize for additional digestion.

The swirling flow pattern in the undulating conduit hydrodynamic mixeris conducive to better abrading and digestion of lumps.

The “folding-over” mixing action of the undulating conduit hydrodynamicmixer enhances the contact and attachment of air to the oil dropletsthus enhancing the conditioning of the slurry.

Economy of Development of the Invention Prototype. Since the undulatingconduit hydrodynamic mixer system is based on principles of hydraulicflow, most of its parameters can be established theoretically and anumerical model developed and proven experimentally within a relativelyshort time and at a reasonable cost.

The Undulating Conduit Hydrodynamic Mixer Can Be Utilized in SeveralPhases of Mixing, Transport and Separation. The undulating conduithydrodynamic mixer lends itself to use in at least three stages ofmixing, transport and extraction, as illustrated in FIG. 7. Adescription of the oil sand extraction process shown in this Figure isprovided in the following sections.

Stage #1—Undulating conduit hydrodynamic mixer (B) inserted as ahydro-dynamic mixer between contactor (A) and sand settler (D). The oilsand slurry is preconditioned in the contactor (A) as dense media.Contactor (A) is shown as a pug mill in FIG. 7. However, this functioncould also be provided by an undulating conduit hydrodynamic mixer.

After one or two minutes of mixing, the slurry is diluted and pumpedthrough the undulating conduit hydrodynamic mixer (B) where it isfurther conditioned before entering the sand settler (D) and cyclodistributor (C). The diluted dense media slurry stream (8) will have atypical weight composition of approximately 65% solids, 10% bitumen andthe remainder water. The components of the diluted dense media must stayin suspension between (A) and (D) to prevent conglomerates forming fromthe solids, bitumen and fines. The swirling flow of the undulatingconduit hydrodynamic mixer keeps these components in suspension untilthe slurry reaches the flotation stage. This also prevents rapid conduitwear that would otherwise be caused by settled solids sliding between(A) and (D).

In Stage #2, the introduction of the undulating conduit hydrodynamicmixer (E) in transportation of the oil-laden middlings from the sandsettler (D) to the froth separator (F) prevents premature coalescence ofaerated oil globules and solids. The undulating conduit hydrodynamicmixer maintains the contents as a well-mixed suspension so that they canbe evenly distributed across the Froth Separator area to yield optimumproduct.

In stage #3, the undulating conduit hydrodynamic mixer (H) will transfermiddlings from the froth separator (F) to the contactor (A), to be usedas a slurry dilution stream. The function of the undulating conduithydrodynamic mixer between (F) and (A) is to maintain a homogeneousfluid suspension and thereby prevent formation of viscous amalgams thatcould restrict the flow. The working of this system enhances oilrecovery by bringing the unaerated oil droplets back into the system,and also recycles fines that enhance transport of the slurry.

In stage #4, the undulating conduit hydrodynamic mixer (T) will transfertailings from the sand separator (D) to the tailings disposal area. Thetailings stream (16) will have a typical weight composition ofapproximately 65% coarse and fine solids, less than 2% bitumen and theremainder water. The function of the undulating hydrodynamic mixingconduit (T) is to maintain a well-fluidized tailings slurry that can bepumped at high density without causing rapid localized abrasive wear dueto settled solids sliding along the conduit bottom. The undulatinghydrodynamic mixing conduit will also be resistant to plugging withsettled solids during a tailings line shutdown.

Mobility of the Undulating Conduit Hydrodynamic Mixer. The undulatingconduit hydrodynamic mixer can be structured to be compact and mobile,so that it can be moved about in the mining sites if necessary.

Cost Effectiveness. The undulating conduit hydrodynamic mixer candisplace some of the mixing equipment which is in current use at aconsiderably lower capital cost, lower operational and maintenance cost,and reduced down time to repair and/or replace worn out equipment.

The Process Described in the Application of this Invention. Oil sandscontain sharp, various sized grains of sand particles, bitumen (a highviscosity oil) and connate water containing various amounts of corrosivechlorides. Conditioning starts in contactor (A) with the addition offresh water, middlings from froth separator and chemicals if required.

The next step in preparation of slurry is accomplished in thehydrodynamic mixer, where it will be gently conditioned by thoroughlymixing while air, chemicals, predetermined energy and set time will beapplied.

The next function is accomplished in the sand settler (D). Here, theslurry is diluted, mixed with recycled middlings in the cyclodistributor(C) followed by settling of the sand and floating of oil and middlings.

Settled sand, diluted by tailings from secondary oil recovery is removedfor disposal while oil and floating middlings are transported byundulating conduit hydrodynamic mixer, to prevent coalescence of aeratedoil droplets with high solids middlings, to the Froth Separator (“F”).In this stage of process, oil is floated off and removed as final frothwhile middlings containing liquid, some oil and fines (solid particlesusually less than 44 microns), are recycled to the Contactor.

Static Undulating Conduit Hydrodynamic Mixer Management of Settling andFlotation Problems. The transport of slurry in straight pipes is subjectto the problem of blockage caused by solids. At times of reducedvelocities and/or stoppage, heterogeneous slurries, such as oil sandslurry, settle rapidly to form a sandy or hard deposit.

Similarly, in particular when processing high oil content ore (+12%),the spontaneous rise of aerated oil droplets forms a viscous amalgam atthe top of the conduit, which increases in size with time of travel,building up system pressure and restricting the flow of slurry.

Solids suspended in the aerated viscous amalgam layer also cause highconduit wear where this layer slides along the conduit walls. Theviscous amalgam layer is dispersed, or is prevented from forming, by thelow-shear mixing action of slurry flow within the undulating conduithydrodynamic mixer.

The undulating conduit hydrodynamic mixer will overcome the abovedeteriorating conditions, even at the low fluid velocities of laminarflow, by keeping the slurry in a state of gentle swirling flow. Theslurry is subjected to continuous flow direction changes, vortexing androtation, and as a result the elements are kept in motion.

Undulating Conduit Hydrodynamic Mixer Management of Abrasion Problem. Bykeeping solids in suspension the abrasive aspect of moving sand will bereduced. The velocity can be reduced without loss of mixing benefit; thesands are evenly distributed within the slurry, which also minimizes theabrasive effect on the walls of the conduit. With the sands incontinuous suspension there is no settlement to the bottom of theconduit to create uneven wear on its base. In other words, the totalwear factor is both reduced and spread out evenly within the pipe.

Applications. This invention offers a great range of potentialapplications. It is a mixer and can also serve as a materialstransporter that incorporates a controlled mixing function.

Some uses are oil extraction from Alberta oil sands (water wet sandgrains); U.S. oil sands (oil coated sand grains); and oil sands depositsin other parts of the world.

Various utilities such as water treatment plants and sewage treatmentplants.

Industrial uses such as petrochemical industries, various solidstransport industries such as transport of potash ore, coal and othermined minerals, dredging of harbors and rivers, paint manufacturing, andthe food preparation industry. It can enhance and improve existingsystems by the principle of the undulating conduit apparatus.

One particular use to which this invention is suited is in theextraction of oil from the Fort McMurray oil sands deposits in thevicinity of the Athabasca River in northeastern Alberta, Canada. Becauseof the smaller size of the apparatus, its low capital cost, loweroperating expenses and portability, this invention has potential toallow the development of marginal oil sands deposits by small-scaleoperators.

This capability may be of benefit to less prosperous countries andsmaller regional economies that have oil sands deposits.

Explanation of Flow Diagram (FIG. 7) Showing Utilization of StaticUndulating Conduit Hydrodynamic Mixer in the Proposed Oil ExtractionProcess.

FIG. 7 is an example flow sheet for a method of separating oil from oilsands.

Contactor (A). The contactor is a sturdy mixing device forpreconditioning of the oil sand slurry. The Contactor accomplishes oilsand lump digestion efficiently with a minimum of emulsification of thebitumen. A Pug Mill contactor can perform the required oil sand lumpdigestion and slurry preconditioning, or alternatively an UndulatingConduit Hydrodynamic Mixing contactor can be used for this purpose.

The contactor can be mounted and operated on mobile trailers, thusincreasing mining flexibility. Retention time at this stage shouldpreferably be short (a minute or two) while holding slurry consistencyaround 25% liquid by weight (including connate water).

The temperature of slurry at this stage, should be maintained around30-55° C., to enhance diminution of tar sand lumps, thus liberatingbitumen matrix intact.

To control the density of the above slurry, a stream (4) containingrecycled middlings from the froth separator (F), chemicals and possiblyfresh water is added.

After mixing is completed, this slurry (5) overflows the lip of thecontactor and then falls through the screen into the pump hopper.

Fresh hot water (6) or a recycle stream (11) can be applied to diluteand propel this slurry through the screen openings, as well as to washattached oil off the rejected oversize lumps (7).

The size of rejects (7) is dictated by the handling capability of thedownstream equipment, in this case, the diameter of Undulating ConduitHydrodynamic Mixer (B). During cold winter months, rejects containingfrozen lumps of undigested oil sand might be recycled back to theContactor (A).

Process Additives. The final adjustment of slurry density, the slurrypH, as well as addition of dissolved air, can be made via stream (17),before it enters the Undulating Conduit Hydrodynamic Mixer. Using theundulating conduit (in contrast to a straight pipe), the addition ofdissolved air could be tolerated without increasing the flowstratification and possible pipe wear by aerated viscous amalgam.

The screened preconditioned slurry with additives (17) is pumped throughthe Undulating Conduit Hydrodynamic Mixer. For effective mixing, one totwo minutes of retention time should be adequate.

Static Hydrodynamic Mixer Undulating Conduit. The static hydrodynamicmixer undulating conduit can be used in various configurations tofulfill different functions. In FIG. 7, five static hydrodynamic mixerundulating conduits are utilized (shown as B, E, H, T and W). Thehydrodynamic mixer can be utilized firstly as a pure mixer to blendfluid components together. Secondly, it can be utilized as a transportermixer to simultaneously mix and transport the conduit contents. Thirdly,it can serve as inserts in a transportation pipe system to revitalizethe contents in transit.

The static hydrodynamic mixer undulating conduit can be used as a mixeronly, by applying a small length of conduit having undulations of ashort pitch configuration. This static hydrodynamic mixer undulatingconduit unit could be mounted on mobile equipment and operated close tothe mining area.

The static hydrodynamic mixer undulating conduit could also consist of acombined mixing and transport system having continuous long-pitchundulations or a combination of straight pipes with insertions ofundulating pipes. The correct design of this unit, establishing lengthand diameter of conduit, and diameter and pitch of the undulation, couldpositively influence the product quality and reduce related expenses.

Sand Settler (D). Sand accounts for around 80% of the oil sand weight.As much sand as possible should be removed from the slurry as early aspossible to avoid abrasive wear on downstream equipment. The sandsettler should therefore be installed as near as possible to the mine toreduce the need to transport large volumes of solids out of the minearea.

Conditioned slurry (8) is introduced into the sand settler (D) by meansof the cyclodistributor (C). Here it is dispersed and diluted byrecycled middlings stream (9), which also induces additional rotationalmomentum. The resulting motion enhances turbulence within the middlingsin the lower section of the vessel, thus preventing the formation ofgels (pseudo-plastic behavior).

The cyclonic action within the cyclodistributor enhances the separationof sand and aerated oil droplets by means of turbulence and densitydifferential.

After exiting the cyclodistributor, rising aerated oil droplets and somemiddlings are floated to the top of the vessel and then leave the sandseparator by means of a stream (10) which passes through an UndulatingConduit Hydrodynamic Mixer (E) functioning as a transporter/mixer thatprevents conglomeration and stratification of aerated oil droplets.

The sand-laden portion of the slurry is discharged onto the conicaldeflector where it fans and spreads out. This allows any oil carried bythe outflowing stream to escape. The released oil rises to the top,while the descending sand is uniformly distributed across the lowerportion of the sand settler.

As the sand slides down the walls and settles towards the bottom of thesettler, it densifies and releases middlings fluid and bitumen. Thebuild-up of densified sand on the bottom creates a sand-middlingsinterface that acts as a seal to exclude oil-bearing middlings from thetailings stream (16).

The flux of released middlings and bitumen creates an upward flowcurrent towards the cone under the cyclone distributor, where thereleased middlings and bitumen join stream (9).

The density of tailings stream (16) drawn from the bottom of the vessel,is controlled by injection of secondary oil recovery tailings (15).

Froth Separator (F). Oil-enriched middlings stream (10) is transportedfrom the sand settler to the froth separator by means of the UndulatingConduit Hydrodynamic Mixer, which prevents coagulation of aerated oildroplets. The stream enters the froth separator via the rotarydistributor (K) and is laid down unifoimly across the vessel.

Streams exiting the rotating distributor (K) are mixed with surroundingliquid and, thus diluted, are the first step of the actual process ofseparation.

The released aerated oil globules rise to the top of the vessel, wherethey form a bituminous froth (13), while coarse and fine sand particles,and some unaerated bitumen, settle to the bottom of the froth separator.

Underwash. Fresh (pretreated) underwash water is introduced preferablyby way of underwash rotary distributor (J) beneath the froth layer, butabove the oil enriched middlings distributor (K). In this way, a highlydiluted zone is provided, through which the ascending bitumen passesimmediately before joining the froth. This step contributes to formationof higher froth quality by washing rising aerated bitumen droplets andmaintaining a mild downward current that depresses the fines to themiddlings withdrawal pipe (11). There is usually more underwash waterthan middlings water in the froth product, suggesting that only excessunderwash water is involved in the downward flow. The dilute underwashzone leads not only to clean froth, but also maintains stable operationeven when high fines oil sands are being processed.

Primary Froth. Rising to the surface, aerated oil globules form a froth(13), on average containing 60-70% oil, 6-10% solids and 20-30% water,which overflows into launders and is pumped to froth treatmentfacilities. An Undulating Conduit Hydrodynamic Mixer (W) may be asuitable apparatus for washing the froth. Froth washing gently shearsand stretches conglomerated droplets of aerated bitumen that havetrapped solids and water in the interstices between the clumpeddroplets. The gentle low-shear scrubbing action of fluid motion insidethe undulating conduit (W) liberates the trapped solids and water in thefroth without creating an emulsion and moving solids towards and closeto walls of the conduit by centrifugal force, to be removed, shortlybefore discharging a product.

Middlings Recycle. The middlings for recycle to the contactor (11) aretaken from the froth separator via a collector pipe. By this means acertain percentage of solids (mostly as fines) are removed from thecenter of the froth separator (F). The withdrawal of stream (11) createsgentle shear within the center zone of the froth separator, which helpsprevent the remaining fines from coalescing or gelling. Stream (11)should be transferred to the contactor (A) via Undulating ConduitHydrodynamic Mixer to prevent formation of viscous amalgams that couldrestrict the flow.

Secondary Oil Recovery. Froth separator tailings (12) are withdrawn andintroduced into the secondary oil recovery system (G).

Secondary Oil Recovery Froth. The product of secondary oil recoverysystem (14), a froth high in solids, which is introduced into middlingsrecycle stream (9) and forwarded to the cyclodistributor.

Secondary Oil Recovery Tailings. A low oil content discharge stream (15)from the secondary oil recovery circuit enters the sand settler (D) as asand tailings dilution and fluidizing stream.

Sand Separator (D) Tailings. A high-solids, low oil content dischargestream (16) leaves the Sand Settler (D) and is pumped to the SandTailings disposal area via an Undulating Hydrodynamic Mixing Conduit(T). The function of this undulating mixer conduit is to maintain awell-fluidized tailings slurry that can be efficiently pumped at highdensity without excessive wear of the conduit due to sliding stratifiedsolids. The undulating conduit is also resistant to plugging withsettled solids during a tailings line shutdown.

It will be appreciated that the terms conduit and pipe are usedinterchangeably herein.

Although the invention has been described with respect to bending pipesfor application in oil field slurry transport, it will be appreciatedthat the undulating helical pipe may be utilized for any suitableapplication.

For further discussion of undulating helical pipe, please seeApplicant's U.S. patent application Ser. No. 11/525,668, filed on Sep.22, 2006; U.S. patent application Ser. No. 10/736,485, filed on Dec. 15,2003, now abandoned; and U.S. provisional patent application No.60/392,281, filed on Jun. 28, 2002, as well as U.S. Pat. No. 6,896,007,all of which are incorporated herein by reference.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventor for carrying out the invention.Variations of these preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventor expects skilled artisans to employ such variations asappropriate, and the inventor intends for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

1. A method of forming an undulating pipe comprising: providing asubstantially straight pipe having a longitudinal axis through thecenter of the pipe; providing a bending apparatus including a system forfeeding the pipe through the bending apparatus; moving the pipe in anaxial direction through the bending apparatus, the bending apparatusasserting a force on the pipe to arcuately bend the pipe; andsimultaneously rotating the pipe about the longitudinal axis as the pipeis moving in the axial direction such that the pipe undulates in agenerally helical path.
 2. The method of claim 1 wherein the bendingapparatus includes a plurality of rollers.
 3. The method of claim 2wherein the bending apparatus comprises a feed roller and a bendingroller.
 4. The method of claim 1 wherein the interior of the pipeincludes a continuous smooth interior wall throughout a length of thepipe.
 5. The method of claim 1 wherein the pipe has an interior wallthat is circular in cross-section at every position along a length ofthe pipe.
 6. The method of claim 1 wherein the pipe is moved and rotatedat rates such that the pitch is substantially greater than one pipediameter.
 7. The method of claim 6 wherein the pipe is moved and rotatedat rates such that the pitch is a multiple of the pipe diameter.
 8. Themethod of claim 1 wherein the pipe is moved and rotated at rates suchthat the radius of the helical path is smaller than the radius of theinterior of the pipe.